Officials said subway service resumed Sunday afternoon on the orange and red lines. The green line also has resumed from Kenmore Station to Lechmere. The Blue Line is running through to Wonderland.

Bus service is running on 18 routes.

The T had originally said it was not expecting to restore service until Monday as workers cleaned up from the massive snowstorm that dumped several feet of snow throughout the Northeast.

MBTA General Manager Beverly Scott said that although the system still faces challenges from the heavy snow, officials hope to have all subways, buses and commuter trains running for Monday morning's commute.

"Give yourself more time and expect that it is going to take us more time," Scott advised customers. "But we are going to be fully operational."